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Li B, Xu XM, Wu YQ, Miao XQ, Feng Y, Chen YC, Salvi R, Xu JJ, Qi JW. The relationship between changes in functional connectivity gradients and cognitive-emotional disorders in sudden sensorineural hearing loss. Brain Commun 2024; 6:fcae317. [PMID: 39318785 PMCID: PMC11420982 DOI: 10.1093/braincomms/fcae317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 07/02/2024] [Accepted: 09/18/2024] [Indexed: 09/26/2024] Open
Abstract
Sudden sensorineural hearing loss, a prevalent emergency in otolaryngology, is known to potentially precipitate cognitive and emotional disorders in affected individuals. Extensive research has documented the phenomenon of cortical functional reorganization in patients with sudden sensorineural hearing loss. However, the potential link between this neural functional remodelling and cognitive-emotional disorders remains unclear. To investigate this issue, 30 bilateral sudden sensorineural hearing loss patients and 30 healthy adults were recruited for this study. We collected clinical data and resting-state functional magnetic resonance imaging data from the participants. Gradient mapping analysis was employed to calculate the first three gradients for each subject. Subsequently, gradient changes in sudden sensorineural hearing loss patients were compared with healthy controls at global, regional and network levels. Finally, we explored the relationship between gradient values and clinical variables. The results revealed that at the global level, sudden sensorineural hearing loss did not exhibit significant differences in the primary gradient but showed a state of compression in the second and third gradients. At the regional level, sudden sensorineural hearing loss patients exhibited a significant reduction in the primary gradient values in the temporal pole and ventral prefrontal cortex, which were closely related to neuro-scale scores. Regarding the network level, sudden sensorineural hearing loss did not show significant differences in the primary gradient but instead displayed significant changes in the control network and default mode network in the second and third gradients. This study revealed disruptions in the functional hierarchy of sudden sensorineural hearing loss, and the alterations in functional connectivity gradients were closely associated with cognitive and emotional disturbances in patients. These findings provide new evidence for understanding the functional remodelling that occurs in sudden sensorineural hearing loss.
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Affiliation(s)
- Biao Li
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Xiao-Min Xu
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Yuan-Qing Wu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Xiu-Qian Miao
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Yuan Feng
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Yu-Chen Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, The State University of New York, Buffalo, NY 14214, USA
| | - Jin-Jing Xu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Jian-Wei Qi
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
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Schwaderlapp N, Paschen E, LeVan P, von Elverfeldt D, Haas CA. Probing hippocampal stimulation in experimental temporal lobe epilepsy with functional MRI. FRONTIERS IN NEUROIMAGING 2024; 3:1423770. [PMID: 39205946 PMCID: PMC11349577 DOI: 10.3389/fnimg.2024.1423770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024]
Abstract
Electrical neurostimulation is currently used to manage epilepsy, but the most effective approach for minimizing seizure occurrence is uncertain. While functional MRI (fMRI) can reveal which brain areas are affected by stimulation, simultaneous deep brain stimulation (DBS)-fMRI examinations in patients are rare and the possibility to investigate multiple stimulation protocols is limited. In this study, we utilized the intrahippocampal kainate mouse model of mesial temporal lobe epilepsy (mTLE) to systematically examine the brain-wide responses to electrical stimulation using fMRI. We compared fMRI responses of saline-injected controls and epileptic mice during stimulation in the septal hippocampus (HC) at 10 Hz and demonstrated the effects of different stimulation amplitudes (80-230 μA) and frequencies (1-100 Hz) in epileptic mice. Motivated by recent studies exploring 1 Hz stimulation to prevent epileptic seizures, we furthermore investigated the effect of prolonged 1 Hz stimulation with fMRI. Compared to sham controls, epileptic mice showed less propagation to the contralateral HC, but significantly stronger responses in the ipsilateral HC and a wider spread to the entorhinal cortex and septal region. Varying the stimulation amplitude had little effect on the resulting activation patterns, whereas the stimulation frequency represented the key parameter and determined whether the induced activation remained local or spread from the hippocampal formation into cortical areas. Prolonged stimulation of epileptic mice at 1 Hz caused a slight reduction in local excitability. In this way, our study contributes to a better understanding of these stimulation paradigms.
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Affiliation(s)
- Niels Schwaderlapp
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Medical Center Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg im Breisgau, Germany
| | - Enya Paschen
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
| | - Pierre LeVan
- Department of Radiology and Paediatrics, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Dominik von Elverfeldt
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University Medical Center Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
| | - Carola A. Haas
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg im Breisgau, Germany
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg im Breisgau, Germany
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Lyu D, Stiger J, Lusk Z, Buch V, Parvizi J. Causal Cortical and Thalamic Connections in the Human Brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.22.600166. [PMID: 38979261 PMCID: PMC11230252 DOI: 10.1101/2024.06.22.600166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The brain's functional architecture is intricately shaped by causal connections between its cortical and subcortical structures. Here, we studied 27 participants with 4864 electrodes implanted across the anterior, mediodorsal, and pulvinar thalamic regions, and the cortex. Using data from electrical stimulation procedures and a data-driven approach informed by neurophysiological standards, we dissociated three unique spectral patterns generated by the perturbation of a given brain area. Among these, a novel waveform emerged, marked by delayed-onset slow oscillations in both ipsilateral and contralateral cortices following thalamic stimulations, suggesting a mechanism by which a thalamic site can influence bilateral cortical activity. Moreover, cortical stimulations evoked earlier signals in the thalamus than in other connected cortical areas suggesting that the thalamus receives a copy of signals before they are exchanged across the cortex. Our causal connectivity data can be used to inform biologically-inspired computational models of the functional architecture of the brain.
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Affiliation(s)
- Dian Lyu
- Laboratory of Behavioral and Cognitive Neuroscience, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California USA
| | - James Stiger
- Laboratory of Behavioral and Cognitive Neuroscience, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California USA
| | - Zoe Lusk
- Laboratory of Behavioral and Cognitive Neuroscience, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California USA
| | - Vivek Buch
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California USA
| | - Josef Parvizi
- Laboratory of Behavioral and Cognitive Neuroscience, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California USA
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Parvizi J, Lyu D, Stieger J, Lusk Z, Buch V. Causal Cortical and Thalamic Connections in the Human Brain. RESEARCH SQUARE 2024:rs.3.rs-4366486. [PMID: 38853954 PMCID: PMC11160924 DOI: 10.21203/rs.3.rs-4366486/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The brain's functional architecture is intricately shaped by causal connections between its cortical and subcortical structures. Here, we studied 27 participants with 4864 electrodes implanted across the anterior, mediodorsal, and pulvinar thalamic regions, and the cortex. Using data from electrical stimulation procedures and a data-driven approach informed by neurophysiological standards, we dissociated three unique spectral patterns generated by the perturbation of a given brain area. Among these, a novel waveform emerged, marked by delayed-onset slow oscillations in both ipsilateral and contralateral cortices following thalamic stimulations, suggesting a mechanism by which a thalamic site can influence bilateral cortical activity. Moreover, cortical stimulations evoked earlier signals in the thalamus than in other connected cortical areas suggesting that the thalamus receives a copy of signals before they are exchanged across the cortex. Our causal connectivity data can be used to inform biologically-inspired computational models of the functional architecture of the brain.
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Wisłowska-Stanek A, Turzyńska D, Sobolewska A, Kołosowska K, Szyndler J, Skórzewska A, Maciejak P. The effect of valproate on the amino acids, monoamines, and kynurenic acid concentrations in brain structures involved in epileptogenesis in the pentylenetetrazol-kindled rats. Pharmacol Rep 2024; 76:348-367. [PMID: 38519733 DOI: 10.1007/s43440-024-00573-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 03/25/2024]
Abstract
BACKGROUND The study aimed to assess the influence of a single valproate (VPA) administration on inhibitory and excitatory neurotransmitter concentrations in the brain structures involved in epileptogenesis in pentylenetetrazol (PTZ)-kindled rats. METHODS Adult, male Wistar rats were kindled by repeated intraperitoneal (ip) injections of PTZ at a subconvulsive dose (30 mg/kg, three times a week). Due to the different times required to kindle the rats (18-22 injections of PTZ), a booster dose of PTZ was administrated 7 days after the last rats were kindled. Then rats were divided into two groups: acute administration of VPA (400 mg/kg) or saline given ip. The concentration of amino acids, kynurenic acid (KYNA), monoamines, and their metabolites in the prefrontal cortex, hippocampus, amygdala, and striatum was assessed by high-pressure liquid chromatography (HPLC). RESULTS It was found that a single administration of VPA increased the gamma-aminobutyric acid (GABA), tryptophan (TRP), 5-hydroxyindoleacetic acid (5-HIAA), and KYNA concentrations and decreased aspartate (ASP) levels in PTZ-kindled rats in the prefrontal cortex, hippocampus, amygdala and striatum. CONCLUSIONS Our results indicate that a single administration of VPA in the PTZ-kindled rats restored proper balance between excitatory (decreasing the level of ASP) and inhibitory neurotransmission (increased concentration GABA, KYNA) and affecting serotoninergic neurotransmission in the prefrontal cortex, hippocampus, amygdala, and striatum.
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Affiliation(s)
- Aleksandra Wisłowska-Stanek
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CePT), Medical University of Warsaw, Banacha 1B, 02-097, Warszawa, Poland.
| | - Danuta Turzyńska
- Department of Experimental and Clinical Neuroscience, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957, Warszawa, Poland
| | - Alicja Sobolewska
- Department of Experimental and Clinical Neuroscience, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957, Warszawa, Poland
| | - Karolina Kołosowska
- Department of Experimental and Clinical Neuroscience, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957, Warszawa, Poland
| | - Janusz Szyndler
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CePT), Medical University of Warsaw, Banacha 1B, 02-097, Warszawa, Poland
| | - Anna Skórzewska
- Department of Experimental and Clinical Neuroscience, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957, Warszawa, Poland
| | - Piotr Maciejak
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CePT), Medical University of Warsaw, Banacha 1B, 02-097, Warszawa, Poland
- Department of Experimental and Clinical Neuroscience, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957, Warszawa, Poland
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Wachsmuth L, Hebbelmann L, Prade J, Kohnert LC, Lambers H, Lüttjohann A, Budde T, Hess A, Faber C. Epilepsy-related functional brain network alterations are already present at an early age in the GAERS rat model of genetic absence epilepsy. Front Neurol 2024; 15:1355862. [PMID: 38529038 PMCID: PMC10961455 DOI: 10.3389/fneur.2024.1355862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/16/2024] [Indexed: 03/27/2024] Open
Abstract
Introduction Genetic Absence Epilepsy Rats from Strasbourg (GAERS) represent a model of genetic generalized epilepsy. The present longitudinal study in GAERS and age-matched non-epileptic controls (NEC) aimed to characterize the epileptic brain network using two functional measures, resting state-functional magnetic resonance imaging (rs-fMRI) and manganese-enhanced MRI (MEMRI) combined with morphometry, and to investigate potential brain network alterations, following long-term seizure activity. Methods Repeated rs-fMRI measurements at 9.4 T between 3 and 8 months of age were combined with MEMRI at the final time point of the study. We used graph theory analysis to infer community structure and global and local network parameters from rs-fMRI data and compared them to brain region-wise manganese accumulation patterns and deformation-based morphometry (DBM). Results Functional connectivity (FC) was generally higher in GAERS when compared to NEC. Global network parameters and community structure were similar in NEC and GAERS, suggesting efficiently functioning networks in both strains. No progressive FC changes were observed in epileptic animals. Network-based statistics (NBS) revealed stronger FC within the cortical community, including regions of association and sensorimotor cortex, and with basal ganglia and limbic regions in GAERS, irrespective of age. Higher manganese accumulation in GAERS than in NEC was observed at 8 months of age, consistent with higher overall rs-FC, particularly in sensorimotor cortex and association cortex regions. Functional measures showed less similarity in subcortical regions. Whole brain volumes of 8 months-old GAERS were higher when compared to age-matched NEC, and DBM revealed increased volumes of several association and sensorimotor cortex regions and of the thalamus. Discussion rs-fMRI, MEMRI, and volumetric data collectively suggest the significance of cortical networks in GAERS, which correlates with an increased fronto-central connectivity in childhood absence epilepsy (CAE). Our findings also verify involvement of basal ganglia and limbic regions. Epilepsy-related network alterations are already present in juvenile animals. Consequently, this early condition seems to play a greater role in dynamic brain function than chronic absence seizures.
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Affiliation(s)
- Lydia Wachsmuth
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Leo Hebbelmann
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Jutta Prade
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Laura C. Kohnert
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | | | | | - Thomas Budde
- Institute of Physiology I, University of Münster, Münster, Germany
| | - Andreas Hess
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- FAU NeW – Research Center for New Bioactive Compounds, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Cornelius Faber
- Clinic of Radiology, University of Münster, Münster, Germany
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Rigoni I, Padmasola GP, Sheybani L, Schaller K, Quairiaux C, Vulliemoz S. Reproducible network changes occur in a mouse model of temporal lobe epilepsy but do not correlate with disease severity. Neurobiol Dis 2024; 190:106382. [PMID: 38114050 DOI: 10.1016/j.nbd.2023.106382] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/27/2023] [Accepted: 12/13/2023] [Indexed: 12/21/2023] Open
Abstract
Studying the development of brain network disruptions in epilepsy is challenged by the paucity of data before epilepsy onset. Here, we used the unilateral, kainate mouse model of hippocampal epilepsy to investigate brain network changes before and after epilepsy onset and their stability across time. Using 32 epicranial electrodes distributed over the mouse hemispheres, we analyzed EEG epochs free from epileptic activity in 15 animals before and 28 days after hippocampal injection (group 1) and in 20 animals on two consecutive days (d28 and d29, group 2). Statistical dependencies between electrodes were characterized with the debiased-weighted phase lag index. We analyzed: a) graph metric changes from baseline to chronic stage (d28) in group 1; b) their reliability across d28 and d29, in group 2; c) their correlation with epileptic activity (EA: seizure, spike and fast-ripple rates), averaged over d28 and d29, in group 2. During the chronic stage, intra-hemispheric connections of the non-injected hemisphere strengthened, yielding an asymmetrical network in low (4-8 Hz) and high theta (8-12 Hz) bands. The contralateral hemisphere also became more integrated and segregated within the high theta band. Both network topology and EEG markers of EA were stable over consecutive days but not correlated with each other. Altogether, we show reproducible large-scale network modifications after the development of focal epilepsy. These modifications are mostly specific to the non-injected hemisphere. The absence of correlation with epileptic activity does not allow to specifically ascribe these network changes to mechanisms supporting EA or rather compensatory inhibition but supports the notion that epilepsy extends beyond the sole repetition of EA and impacts network that might not be involved in EA generation.
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Affiliation(s)
- Isotta Rigoni
- EEG and Epilepsy unit, Department of Neuroscience, University Hospital and Faculty of Medicine of Geneva, University of Geneva, Geneva, Switzerland.
| | - Guru Prasad Padmasola
- Department of Basic Neuroscience, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Laurent Sheybani
- EEG and Epilepsy unit, Department of Neuroscience, University Hospital and Faculty of Medicine of Geneva, University of Geneva, Geneva, Switzerland; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Karl Schaller
- Department of Neurosurgery, University Hospital and Faculty of Medicine of Geneva, Geneva, Switzerland
| | - Charles Quairiaux
- Department of Basic Neuroscience, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Serge Vulliemoz
- EEG and Epilepsy unit, Department of Neuroscience, University Hospital and Faculty of Medicine of Geneva, University of Geneva, Geneva, Switzerland
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Lee DA, Lee H, Kim SE, Park KM. Brain networks and epilepsy development in patients with Alzheimer disease. Brain Behav 2023; 13:e3152. [PMID: 37416994 PMCID: PMC10454249 DOI: 10.1002/brb3.3152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/26/2023] [Accepted: 06/26/2023] [Indexed: 07/08/2023] Open
Abstract
INTRODUCTION This study aimed to investigate the association between brain networks and epilepsy development in patients with Alzheimer disease (AD). METHODS We enrolled patients newly diagnosed with AD at our hospital who underwent three-dimensional T1-weighted magnetic resonance imaging at the time of AD diagnosis and included healthy controls. We obtained the cortical, subcortical, and thalamic nuclei structural volumes using FreeSurfer and applied graph theory to obtain the global brain network and intrinsic thalamic network based on the structural volumes using BRAPH. RESULTS We enrolled 25 and 56 patients with AD with and without epilepsy development, respectively. We also included 45 healthy controls. The global brain network differed between the patients with AD and healthy controls. The local efficiency (2.026 vs. 3.185, p = .048) and mean clustering coefficient (0.449 vs. 1.321, p = .024) were lower, whereas the characteristic path length (0.449 vs. 1.321, p = .048) was higher in patients with AD than in healthy controls. Both global and intrinsic thalamic networks were significantly different between AD patients with and without epilepsy development. In the global brain network, local efficiency (1.340 vs. 2.401, p = .045), mean clustering coefficient (0.314 vs. 0.491, p = .045), average degree (27.442 vs. 41.173, p = .045), and assortative coefficient (-0.041 vs. -0.011, p = .045) were lower, whereas the characteristic path length (2.930 vs. 2.118, p = .045) was higher in patients with AD with epilepsy development than in those without. In the intrinsic thalamic network, the mean clustering coefficient (0.646 vs. 0.460, p = .048) was higher, whereas the characteristic path length (1.645 vs. 2.232, p = .048) was lower in patients with AD with epilepsy development than in those without. CONCLUSION We found that the global brain network differs between patients with AD and healthy controls. In addition, we demonstrated significant associations between brain networks (both global brain and intrinsic thalamic networks) and epilepsy development in patients with AD.
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Affiliation(s)
- Dong Ah Lee
- Department of Neurology, Haeundae Paik HospitalInje University College of MedicineBusanRepublic of Korea
| | - Ho‐Joon Lee
- Department of Radiology, Haeundae Paik HospitalInje University College of MedicineBusanRepublic of Korea
| | - Si Eun Kim
- Department of Neurology, Haeundae Paik HospitalInje University College of MedicineBusanRepublic of Korea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik HospitalInje University College of MedicineBusanRepublic of Korea
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Hwang Y, Kadam SD. Targeting Epileptogenesis: A Conceptual Black Hole or Light at the End of the Tunnel? Epilepsy Curr 2021; 21:372-375. [PMID: 34924840 PMCID: PMC8655252 DOI: 10.1177/15357597211030384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Li L, Kumar U, You J, Zhou Y, Weiss SA, Engel J, Bragin A. Spatial and temporal profile of high-frequency oscillations in posttraumatic epileptogenesis. Neurobiol Dis 2021; 161:105544. [PMID: 34742877 PMCID: PMC9075674 DOI: 10.1016/j.nbd.2021.105544] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/18/2021] [Accepted: 11/02/2021] [Indexed: 12/18/2022] Open
Abstract
We studied the role of temporal and spatial changes in high-frequency oscillation (HFO, 80-500 Hz) generation in epileptogenesis following traumatic brain injury (TBI). Experiments were conducted on adult male Sprague Dawley rats. For the TBI group, fluid percussion injury (FPI) on the left sensorimotor area was performed to induce posttraumatic epileptogenesis. For the sham control group, only the craniotomy was performed. After TBI, 8 bipolar micro-electrodes were implanted bilaterally in the prefrontal cortex, perilesional area and homotopic contralateral site, striatum, and hippocampus. Long-term video/local field potential (LFP) recordings were performed for up to 21 weeks to identify and characterize seizures and capture HFOs. The electrode tip locations and the volume of post TBI brain lesions were further estimated by ex-vivo MRI scans. HFOs were detected during slow-wave sleep and categorized as ripple (80-200 Hz) and fast ripple (FR, 250-500 Hz) events. HFO rates and the HFO peak frequencies were compared in the 8 recording locations and across 8-weeks following TBI. Data from 48 rats (8 sham controls and 40 TBI rats) were analyzed. Within the TBI group, 22 rats (55%) developed recurrent spontaneous seizures (E+ group), at an average of 62.2 (+17.1) days, while 18 rats (45%) did not (E- group). We observed that the HFOs in the E+ group had a higher mean peak frequency than the E- group and the sham group (P < 0.05). Furthermore, the FR rate of the E+ group showed a significant increase compared to the E-group (P < 0.01) and sham control group (P < 0.01), specifically in the perilesional area, homotopic contralateral site, bilateral hippocampus, and to a lesser degree bilateral striatum. When compared across time, the increased FR rate in the E+ group occurred immediately after the insult and remained stable across the duration of the experiment. In addition, lesion size was not statistically different in the E+ and E- group and was not correlated with HFO rates. Our results suggest that TBI results in the formation of a widespread epileptogenic network. FR rates serve as a biomarker of network formation and predict the future development of epilepsy, however FR are not a temporally specific biomarker of TBI sequelae responsible for epileptogenesis. These results suggest that in patients, future risk of post-TBI epilepsy can be predicted early using FR.
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Affiliation(s)
- Lin Li
- Department of Neurology, University of California Los Angeles, CA 90095, USA; Department of Biomedical Engineering, University of North Texas, TX 76207, USA.
| | - Udaya Kumar
- Department of Neurology, University of California Los Angeles, CA 90095, USA
| | - Jing You
- Department of Biomedical Engineering, University of North Texas, TX 76207, USA
| | - Yufeng Zhou
- Department of Biomedical Engineering, University of North Texas, TX 76207, USA
| | - Shennan A Weiss
- Depts. of Neurology, Dept. of Physiology and Pharmacology, State University of New York Downstate, Brooklyn, New York 11203, USA; Department of Neurology, New York City Health + Hospitals/Kings County, Brooklyn, NY 11203, USA
| | - Jerome Engel
- Department of Neurology, University of California Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Anatol Bragin
- Department of Neurology, University of California Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA.
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Farina MG, Sandhu MRS, Parent M, Sanganahalli BG, Derbin M, Dhaher R, Wang H, Zaveri HP, Zhou Y, Danbolt NC, Hyder F, Eid T. Small loci of astroglial glutamine synthetase deficiency in the postnatal brain cause epileptic seizures and impaired functional connectivity. Epilepsia 2021; 62:2858-2870. [PMID: 34536233 DOI: 10.1111/epi.17072] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/03/2021] [Accepted: 09/03/2021] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The astroglial enzyme glutamine synthetase (GS) is deficient in small loci in the brain in adult patients with different types of focal epilepsy; however, the role of this deficiency in the pathogenesis of epilepsy has been difficult to assess due to a lack of sufficiently sensitive and specific animal models. The aim of this study was to develop an in vivo approach for precise and specific deletions of the GS gene in the postnatal brain. METHODS We stereotaxically injected various adeno-associated virus (AAV)-Cre recombinase constructs into the hippocampal formation and neocortex in 22-70-week-old GSflox/flox mice to knock out the GS gene in a specific and focal manner. The mice were subjected to seizure threshold determination, continuous video-electroencephalographic recordings, advanced in vivo neuroimaging, and immunocytochemistry for GS. RESULTS The construct AAV8-glial fibrillary acidic protein-green fluorescent protein-Cre eliminated GS in >99% of astrocytes in the injection center with a gradual return to full GS expression toward the periphery. Such focal GS deletion reduced seizure threshold, caused spontaneous recurrent seizures, and diminished functional connectivity. SIGNIFICANCE These results suggest that small loci of GS deficiency in the postnatal brain are sufficient to cause epilepsy and impaired functional connectivity. Additionally, given the high specificity and precise spatial resolution of our GS knockdown approach, we anticipate that this model will be extremely useful for rigorous in vivo and ex vivo studies of astroglial GS function at the brain-region and single-cell levels.
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Affiliation(s)
- Maxwell G Farina
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mani Ratnesh S Sandhu
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Maxime Parent
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Basavaraju G Sanganahalli
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Matthew Derbin
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Roni Dhaher
- Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut, USA
| | - Helen Wang
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Hitten P Zaveri
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Yun Zhou
- Institute for Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Niels C Danbolt
- Institute for Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Fahmeed Hyder
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Tore Eid
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
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12
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Chen G, Zhang Z, Wang M, Geng Y, Jin B, Aung T. Update on the Neuroimaging and Electroencephalographic Biomarkers of Epileptogenesis: A Literature Review. Front Neurol 2021; 12:738658. [PMID: 34512540 PMCID: PMC8429485 DOI: 10.3389/fneur.2021.738658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy is one of the most common debilitating neurological disorders that lead to severe socio-cognitive dysfunction. While there are currently more than 30 antiseizure medications available for the treatment and prevention of seizures, none address the prevention of epileptogenesis that leading to the development of epilepsy following a potential brain insult. Hence, there is a growing need for the identification of accurate biomarkers of epileptogenesis that enable the prediction of epilepsy following a known brain insult. Although recent studies using various neuroimages and electroencephalography have found promising biomarkers of epileptogenesis, their utility needs to be further validated in larger clinical trials. In this literature review, we searched the Medline, Pubmed, and Embase databases using the following search algorithm: "epileptogenesis" and "biomarker" and "EEG" or "electroencephalography" or "neuroimaging" limited to publications in English. We presented a comprehensive overview of recent innovations in the role of neuroimaging and EEG in identifying reliable biomarkers of epileptogenesis.
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Affiliation(s)
- Guihua Chen
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Zheyu Zhang
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Meiping Wang
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Yu Geng
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Bo Jin
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Thandar Aung
- Epilepsy Center, University of Pittsburgh, Pittsburgh, PA, United States
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